Networks on chips NOC proved to be scalable interconnect structures in particular for systems on chip which could become possible solutions for future on chip interconnections between so-called IP blocks, i.e., intellectual property blocks. IP blocks are usually modules on chip with a specific function like CPUs, memories, digital signal processors or the like. The IP blocks communicate with each other via the network on chip. The network on chip is typically composed of network interfaces and routers. The network interfaces serve to provide an interface between the IP block and the network on chip, i.e., they translate the information from the IP block to information which the network on chip can understand and vice versa. The routers serve to transport data from one network interface to another. For best effort communication, there is no guarantee regarding the latency of the throughput of the communication. For guaranteed throughput services, an exact value for the latency and throughput is required.
The communication within a network on chip NOC is typically packet-based, i.e., the packets are forwarded between the routers or between routers and network interfaces. A packet typically consists of a header and payload.
To monitor the data traffic via the network on chip, probes can be attached to components of the network on chip, i.e., routers and network interfaces, and may allow a debugging of data to be generated on-chip. The probes can be organized in a monitoring system as described in “An event-based network-on-chip monitoring service” by Ciordas et al., in Proc. Int'l High-Level Design Validation and Test Workshop (HLDVT), November 2004.
A sniffer probe allows (non-intrusive) an access to functional data from a network link and/or a NoC component. Sniffer probes can be arranged such that they are able to sniff from a connection passing that link. Sniffing is at least part of the data traffic required for debugging and constitutes a requirement for other debug-related components like analyzers or event-generators and data/event-filters. Data generated by sniffers is sent towards the monitoring service access point (MSA) via a debug connection. The monitoring service access point constitutes a centralized access point for the monitoring data. In order to sniff the whole traffic from a connection, the bandwidth required for the debug connection will correspond to more or less to the bandwidth of the sniffed connection.